Positive action switches



July 25, 1967 H. w. HULTS POSITIVE ACTION SWITCHES 2 Sheets-Sheet 1Filed March 16, 1966 "gar/113111 IIIIIIII.

July 25, 1967 H. w. HULTS 3,333,074

POSITIVE ACTION SWITCHES Filed March 16, 1966 2 Sheets-Sheet 2 M 3 m m b6 ..n W. e a x 4 W. .w \N Km 5 H @2 W M. m 6 8 i United States Patent3,333,074 POSITIVE ACTION SWITCHES Harold W. Hults, Waukesha, Wis.,assignor to Cutler- Hammer, Inc., Milwaukee, Wis., a corporation ofDelaware Filed Mar. 16, 1966, Ser. No. 534,719 10 Claims. (Cl. 206-68)This invention relates to positive action switches and more particularlyto manually operable switches having a positive and unyieldingconnection between the operating member and the movable contact for atleast a portion of the operating member movement whereby positive forcemay be applied to open and close the contacts.

While not limited thereto, the invention is especially applicable totoggle switches of the self-enclosed type.

An object of the invention is to provide improved positive actionswitches.

Another object of the invention is to provide an improved switchstructure which enables opening of a circuit under faulty conditions.

A more specific object of the invention is to provide improved switchstructures which insure opening of the switch contacts under sticking orwelding conditions.

Another specific object of the invention is to provide improved meansaffording positive break followed by snap-action opening of an electricswitch.

Another specific object of the invention is to provide improved switchoperating means combining positive force with snap-action and detentholding means.

Another specific object of the invention is to provide improved switchapparatus combining positive action and snap-action operation of wipingcontacts.

Another specific object of the invention is to provide an improvedswitch structure which particularly lends itself to hermetic sealing.

Other objects and advantages of the invention will hereinafter appear.

These and other objects and advantages of the invention and the mannerof obtaining them will best be understood by reference to the followingdescription of exemplary embodiments of positive break switches taken inconjunction with the accompanying drawings, wherein:

FIGURE 1 is a front elevational view partly in section taken along line-11 of FIG. 2 showing a single-pole, double-throw toggle switch withboth contacts open;

FIG. 2 is a cross-sectional view taken through the righthand portion ofthe switch along line 22 of FIG. 1;

FIG. 3 is a cross-sectional view showing a top view of the contactstaken line along line 33 of FIG. 1;

FIG. 4 is a cross-sectional view showing a bottom view of the actuatorblock taken along line 44 of FIG. 1;

FIG. 5 is a cross-sectional view taken along line S-5 of FIG. 2 butmodified to show one contact closed;

FIG. 6 is a cross-sectional view showing a top view of the contactstaken along line 66 of FIG. 5;

FIG. 7 is an exploded isometric view of the combined positive break andsnap-action indexing mechanism of the switch of FIGS. 1 to 6;

FIG. 8 is a bottom view of the indexing plate of the switch of FIGS. 1to 7 affording three-position operation;

.FIG. 9 is a cross-sectional view showing the snap-action mechanismtaken along line 9-9 of FIG. 1; and

FIG. 10 is a fragmentary cross-sectional view like the left-hand portionof FIG. 1 showing a modified indexing plate affording two-positionoperation.

Referring to FIG. 1, there is shown a toggle switch constructed inaccordance with the inventon. This switch is provided with asubstantially rectangular metal housing comprising a cup-shaped baseportion 2 open at the top on the rim of which rests the reduced edgeportion of an indexing plate 4 and a relatively shallow cup-shaped coverportion 6 inverted over the base portion so that its rim rests on thereduced edge portion of indexing plate 4. The adjacent rims of the baseand cover portions are secured to one another as by welding over thereduced edge portion of the indexing plate, this weld being depicted by8 in FIG. 1.

Cover portion 6 is provided with a large hole at its center into whichis rigidly secured a bushing 19 having a cross pin 12 therethrough forpivoting therein an operating member such as a toggle lever 14. Thetoggle lever has a handle portion extending upwardly from the bushing sothat it can be grasped by the hand to operate the switch. The togglelever has a lower end projecting into the housing as shown in FIG. 5 andterminating in a spherical end portion 14a extending into a hole in alaterally reciprocal driving plate 16. Hole 16a is round except forapproximately its upper half which is frustoconical in form to provideclearance as the toggle lever is rocked from the middle position toeither the left or right side. Bushing 10 is threaded externally so thatit can be inserted in a hole in a mounting panel and a nut threadedthereon to secure the switch to the panel.

The switch is provided with sliding contacts so that normal operationmaintains them clean to afford a good electrical connection. As shown inFIGS. 2 and 5, base portion 2 of the switch housing is provided withholes through which stationary contacts 18 and 20 and a movable contactconnector 22 extend from the interior to external terminals whereby theswitch is adapted to be connected to the circuit in which it is used.Each stationary contact 18 and 20 is in the form of a round rod having apartially rounded upper end to afford camming of the associated movablecontact thereon.

Connector 22 is also in the form of a round rod and is provided with areduced upper end portion on which movable contacts 24 and 26 arerotatably mounted. Each movable contact has the form of a flat plateprovided with a hole whereby it is inserted on the reduced end portionof connector 22, one on top of the other. A Washer 28 shown in FIG. 3 isseated against the shoulder of a still further reduced portion and bearsagainst upper contact 26 and said still further reduced end of connector22 is riveted over the washer to secure it rigidly in place and toretain the contacts and permit rotation thereof. A helical compressionspring 30 surrounds connector 22 and is compressed between lower contact24 and an insulating base 32 lining the lower part of base portion 2 ofthe housing. As shown in FIG. 5, this helical spring afiords contactpressure by forcing the movable contacts against the retaining washerwhereby the reduced contacting portion 26a of the movable contact ispressed against the stationary contact.

Each narrow contacting portion 24a and 26a has an upwardly inclinedextension 24b and 26!; shown in FIGS. 2 and 6 to facilitate cammingthereof on top of the associated stationary contact.

Each movable contact is also provided with a cam follower pin 24c and260 riveted in a hole at an intermediate portion thereof and extendingupwardly therefrom into a cam slot 34a in the lower surface of aninsulating actuator block 34 as shown in FIGS. 1, 4 and 5.

The switch is provided with combined positive break and snap-actionmeans for coupling the toggle lever to the movable contact. As shown inFIGS. 1, 2 and 5, this means is mounted above insulating base 32. Thismeans comprises an actuator block 34, a pair of indexing plungers 36 and37 cooperating with indexing plate 4, :driving plate 16 and a number ofhelical springs hereinafter described.

As shown in FIGS. 7 and 9, in addition to the cam slot 34a in its lowersurface, actuator block 34 is provided on its upper'surfac with a frontridge 34b and a similar rear ridge 34c for supporting indexing detentplunger 36 and 37, respectively. Front ridge 34b extends all the wayfrom the left side to the right side of the actuator block and isprovided with round pockets 34d and 34e at the left and right endsextending downwardly thereinto as shown in FIG. 1 for receiving helicalcompression springs '38 and 40, respectively. As will be apparent,downwardly projecting pins 36a and 36b at the opposite ends of indexingplunger 36 extend into springs 38 and 40 and these springs bias thehemispherical upper end portions 36c and 3511 against indexing plate 4.Front ridge 34b of the actuator block is also provided with an elongatedcentral recess 34 for receiving a pair of positioning pins 36e of theindexing plunger. These positioning pins'will bear against the ends ofrecess 34f to kee the indexing plunger in proper registration on theactuator block and to prevent springs 38 and 40 from catching on theedges of their associated pockets. Indexing plunger 38 is similar toplunger 36 and is similarly mounted on rear ridge 34c and biased againstthe indexing plate.

The actuator block is provided with means at the center between thefront and rear ridges for mounting the snapaction mechanism comprisingdriving plate 16 and compression springs 42 and 44. This means comprisesa pair of center ridges 34g and 34h extending from the left and rightends, respectively, toward the center and providing a spacetherebetween. These center ridges are provided with elongated pockets341 and 34k open at the top and toward the center space for receivinghelical compression springs 42 and 44, respectively. As will beapparent, these compression springs cooperate with the driving plate toprovide the snap-action to the actuator block. For this purpose, drivingplate 16 which is substantially rectangular in form is provided with adownwardly projecting cross molded integrally on the lower surfacearound hole 16a as shown in FIG. 7. The front and rear arms 16b and 16cof this cross lie in the center space between ridges 34g and 3411 and inthe channels between the front and center and rear ridges as shown inFIG. 9 so that they will abut the opposed inner ends of center ridges34g and 34h after the energy storing motion is taken up. The left andright arms 16d and 16a of this cross extend slightly into pockets 341'and 341: when the toggle lever is in its center position as shown inFIG. 9 and abut the ends of compression springs 42 and 44 whereby thelatter tend to maintain driving plate 16 centered on the actuator block.

As shown in FIGS. 2, 3 and 6, the upper surfaces of base 32 are providedwith grooves 32a, each having a steel ball bearing 32b extendingslightly above these surfaces on which actuator block 34 rolls when theswitch is operated.

From the foregoing, it will be recalled that indexing plungers 36 and 37have hemispherical portions at their ends which are resiliently pressedagainst indexing plate 4. For cooperation therewith, indexing plate 4 isprovided with four sets of downwardly beveled holes 4a as shown in FIGS.1, 2 and 8 into which the rounded end portions of the indexing plungersstop when the toggle lever is reciprocated and into which they areaccelerated by the beveled edges of the holes. This plate is providedwith a large hole 4b at the center to afiord clearance for the togglelever.

As shown in FIG. 8, for a three-position switch each set has three holes4a. For the switch illustrated in FIGS.

1 to .9, which is a single-pole, double-throw switch, these three holesin each set afford a center off or switch open position and left andright closed positions.

As shown in FIGS. 1, 2 and 5, a steel plate 46 is rigidly secured as bywelding to the bottom of the switch base portion 2 of the housing tothicken the bottom. This plate has holes coextensive with and inregistration with the holes in the base portion which are substantiallylarger than the stationary contact connectors extending therethrough toaccommodate insulation. These holes are filled with vitreous or ceramicmaterial 50 or the like which has the qualities of strength, sealing andelectrically insulating. As will be apparent, this material rigidlysecures stationary contacts 18 and 20 and connector 22 to the baseportion of the housing and electrically insulates them from the latter.This securing and scaling is accomplished by different coeflicients ofexpansion of the materials whereby the metal shrinks around the glassseal and grips it.

A modified indexing plate 48 is shown in FIG. 10 which affords atwo-position switch having no center stopping position for the togglelever. As shown in FIG. 10, the center hole of each set of three holesin FIG. '8 has been eliminated and replaced by a bidirectional cam 48asloping from the center in opposite directions to both of the remainingholes 48b. It will be apparent that when the hemisphere of the indexingplunger has been moved across the high point of cam 48a, this caminvoluntarily snaps the indexing plunger and the actuator block assemblyto the position toward which it was being moved.

It will be apparent that in FIG. 1, the switch-is shown in the off oropen contact position. If the toggle lever is pivoted clockwise, thelower ball end of the lever initially moves driving plate 16 in theleft-hand direction against the force of spring 42 until arms 16b and16c of the driving plate abut the inner end of ridge 34g of the actuatorblock. This movement has stored potential energy in spring 42. Furthermovement of the toggle lever in the same direction causes positivemovement of the actuator block in the left-hand direction. As a result,slot 34a in FIG. 4 positively cams pin 26c and movable contact 26rigidly secured thereto rearwardly'to cause end 26a of the movablecontact to be cammed or slid up on the end of stationary contact 20 asshown in FIG. 5.

It will be apparent that the latter part of this contact movement occurswith a snap action. When the toggle lever has been moved to cause thehemisphere of the indexing plungers to cam out of the center holes inthe hole groups in the indexing plate, the aforementioned po-. tentialenergy comes into play. That is, spring 42 now snaps the actuator blockin the left-hand direction all the way until these hemispheres stop inthe left holes in the indexing plate. During this snap action, themovable contact is slid onto the stationary contact. During this closureof contact 26, the other movable contact remains open since the linearpart of slot 34a traverses pin 240.

When the toggle lever is moved in the counterclockwise direction fromthe position shown in FIG. 5, spring 44 is first compressed until thereoccurs an unyielding connection between the toggle lever and movablecontact 26 through driving plate 16, actuator block 34 and pin 260. Thisunyielding connection affords positive break of any weld betweencontacts 20 and 26 and then the movable contact snaps open to reducearcing which would occur if the contacts were open slowly particularlywhen alternating current is interrupted.

While the apparatus hereinbefore described is effectively adopted tofulfill the objects stated, it is to be understood that I do not intendto confine my invention to the particular preferred embodiments ofpositive break switches disclosed, inasmuch as they are susceptible of.various modifications without departing from the scopeof the appendedclaims.

I claim:

1. In an electric switch, the combination comprising:

an insulating base;

a stationary contact mounted in said base;

a movable contact and means mounted in said base for mounting saidmovable contact for rotary movement into and out of engagement with saidstationary contact; an actuator block mounted for'sliding movement alongsaid base and having a camming slot provided with at least a portionextending away from the path of said sliding movement;

a manually operable lever and means providing an unyielding connectionbetween said lever and said actuator block for at least a portion of thelever movement to transmit positive force for closing or opening thecontacts;

and a cam follower rigidly secured to said movable contact and extendinginto engagement with said portion of said camming slot for rotatablyactuating said movable contact into and out of engagement with saidstationary contact when said manually operable lever is reciprocated.

2. The invention defined in claim 1, together with:

potential energy storing means effective in response to initial movementof said manually operable lever for storing energy without moving saidactuator block;

said unyielding connection means being responsive to further movement ofsaid manually operable lever for moving said actuator block;

and means responsive during said further movement for rendering saidpotential energy storing means effective to cause snap-action movementof said actuator block.

3. The invention defined in claim 1, wherein said means mounting saidmovable contact for rotary movement comprises:

a connector rod extending through the bottom of said base and having anenlarged end portion Within said base;

a hole in said movable contact through which said connector rod extends;

and a spring biasing said movable contact against said enlarged endportion wherein said movable contact is normally offset from the planeof the contacted portion of said stationary contact to provide contactpressure when said movable contact is deflected from the plane itoccupies in its open condition onto said stationary contact.

4. The invention defined in claim 1, together with:

indexing means for holding said actuator block in any one of a number ofdifierent operating positions comprising:

a spring biased indexing plunger mounted on said actuator block andhaving hemispherical portions; and a stationary indexing plate againstwhich said hemispherical portions are resiliently pressed and havingholes for retaining the latter in any one of a number of differentoperating positions.

5. The invention defined in claim 4, wherein said indexing platecomprises:

a bidirectional cam between the holes for enhancing movement of saidhemispherical portions toward the holes under the influence of thespring biased force on said indexing plunger.

6. The invention defined in claim 1, wherein said means mounting saidmovable contact for rotary movement comprises:

a connector member extending through the bottom of the base and having awasher secured to the end thereof;

said movable contact being flat and having a hole through which saidconnector member extends;

a spring between said base and said movable contact biasing the latteragainst said washer;

and said connector member normally holding said movable contact in aposition offset relative to the stationary contact so that said movablecontact must be deflected from its normal place when it is cammed ontosaid stationary contact whereby said spring provides contact pressure.

7. In an electric switch, the combination comprising:

an insulating base;

a stationary contact mounted in said base;

a movable contact and means mounting said movable contact for movementinto and out of engagement with said stationary contact;

a switch operating member;

and combined positive break and snap-action means mounted between saidswitch operating member and said movable contact comprising:

an actuator block mounted for reciprocal sliding movement on said baseand engaging said movable contact;

a driving plate engageable by said switch operating member for movementthereby;

spring means between said driving plate and said actuator blockpermitting limited movement of said driving plate relative to saidactuator block against the force of said spring means to store potentialenergy;

means on said driving plate and said actuator block causing positiveengagement therebetween beyond said limited movement thereby providingan unyielding connection from said switch operating means to saidmovable contact to afford positive breaking of the contacts andthereafter said compressed spring means causing snap action of saidactuator block;

a spring-biased detent member having rounded portions mounted on top ofsaid actuator block beside said driving plate;

and a stationary indexing plate above said detent member and havingrecesses for receiving said rounded portions to cause said detent memberto hold said actuator block during said limited movement of said drivingplate.

8. The invention defined in claim 7, wherein said means on said drivingplate and said actuator block comprise:

a pair of tandem ridges with a space therebetween on said actuatorblock;

pockets in said ridges for receiving said spring means and communicatingwith said space;

and a depending cross molded integrally on said driving plate and havingtandem arms bearing against said spring means and lateral arms in saidspace for engaging said ridges after said limited movement.

9. The invention defined in claim 7, wherein said switch is providedwith:

a housing comprising two parts clamping the edge of said indexing platetherebetween and welded together over the edge of said indexing plate.

10. The invention defined in claim 7, wherein said switch operatingmember comprises:

a toggle lever pivoted for reciprocal movement and having asubstantially spherical end;

and a tapered recess in said driving plate into which said spherical endextends and whereby said driving plate is moved.

References Cited UNITED STATES PATENTS 2,335,110 11/1943 Dann 200-63,035,134 5/1962 Hults ZOO-67.7

ROBERT K. SCHAEFER, Primary Examiner. D. SMITH, IR., Assistant Examiner,

1. IN AN ELECTRIC SWITCH, THE COMBINATION COMPRISING: AN INSULATINGBASE; A STATIONARY CONTACT MOUNTED IN SAID BASE; A MOVABLE CONTACT ANDMEANS MOUNTED IN SAID BASE FOR MOUNTING SAID MOVABLE CONTACT FOR ROTARYMOVEMENT INTO AND OUT OF ENGAGEMENT WITH SAID STATIONARY CONTACT; ANACTUATOR BLOCK MOUNTED FOR SLIDING MOVEMENT ALONG SAID BASE AND HAVING ACAMMING SLOT PROVIDED WITH AT LEAST A PORTION EXTENDING AWAY FROM THEPATH OF SAID SLIDING MOVEMENT; A MANUALLY OPERABLE LEVER AND MEANSPROVIDING AN UNYIELDING CONNECTION BETWEEN SAID LEVER AND SAID ACTUATORBLOCK FOR AT LEAST A PORTION OF THE LEVER MOVEMENT TO TRANSMIT POSITIVEFORCE FOR CLOSING OR OPENING THE CONTACTS; AND A CAM FOLLOWER RIGIDLYSECURED TO SAID MOVABLE CONTACT AND EXTENDING INTO ENGAGEMENT WITH SAIDPORTION OF SAID CAMMING SLOT FOR ROTATABLY ACTUATING SAID MOVABLECONTACT INTO AND OUT OF ENGAGEMENT WITH SAID STATIONARY CONTACT WHENSAID MANUALLY OPERABLE LEVER IS RECIPROCATED.